diff mbox series

[1/3] cpufreq: amd-pstate: Add more tracepoint for AMD P-State module

Message ID 20220223100350.3523826-2-Jinzhou.Su@amd.com
State Superseded
Headers show
Series Add tracer tool for AMD P-State driver | expand

Commit Message

Jinzhou Su Feb. 23, 2022, 10:03 a.m. UTC
Add frequency, mperf, aperf and tsc in the trace. This can be used
to debug and tune the performance of AMD P-state driver.

Use the time difference between amd_pstate_update to calculate CPU
frequency. There could be sleep in arch_freq_get_on_cpu, so do not
use it here.

Signed-off-by: Jinzhou Su <Jinzhou.Su@amd.com>
Signed-off-by: Huang Rui <ray.huang@amd.com>
---
 drivers/cpufreq/amd-pstate-trace.h | 22 ++++++++++-
 drivers/cpufreq/amd-pstate.c       | 59 +++++++++++++++++++++++++++++-
 2 files changed, 78 insertions(+), 3 deletions(-)

Comments

Rafael J. Wysocki March 1, 2022, 3:26 p.m. UTC | #1
On Wed, Feb 23, 2022 at 11:04 AM Jinzhou Su <Jinzhou.Su@amd.com> wrote:
>
> Add frequency, mperf, aperf and tsc in the trace. This can be used
> to debug and tune the performance of AMD P-state driver.
>
> Use the time difference between amd_pstate_update to calculate CPU
> frequency. There could be sleep in arch_freq_get_on_cpu, so do not
> use it here.
>
> Signed-off-by: Jinzhou Su <Jinzhou.Su@amd.com>
> Signed-off-by: Huang Rui <ray.huang@amd.com>

I'm not sure what the second sign-off is for.

If this is a maintainer's sign-off, it should be added by the
maintainer himself  and you should not add it when submitting the
patch.

> ---
>  drivers/cpufreq/amd-pstate-trace.h | 22 ++++++++++-
>  drivers/cpufreq/amd-pstate.c       | 59 +++++++++++++++++++++++++++++-
>  2 files changed, 78 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate-trace.h b/drivers/cpufreq/amd-pstate-trace.h
> index 647505957d4f..35f38ae67fb1 100644
> --- a/drivers/cpufreq/amd-pstate-trace.h
> +++ b/drivers/cpufreq/amd-pstate-trace.h
> @@ -27,6 +27,10 @@ TRACE_EVENT(amd_pstate_perf,
>         TP_PROTO(unsigned long min_perf,
>                  unsigned long target_perf,
>                  unsigned long capacity,
> +                u64 freq,
> +                u64 mperf,
> +                u64 aperf,
> +                u64 tsc,
>                  unsigned int cpu_id,
>                  bool changed,
>                  bool fast_switch
> @@ -35,6 +39,10 @@ TRACE_EVENT(amd_pstate_perf,
>         TP_ARGS(min_perf,
>                 target_perf,
>                 capacity,
> +               freq,
> +               mperf,
> +               aperf,
> +               tsc,
>                 cpu_id,
>                 changed,
>                 fast_switch
> @@ -44,6 +52,10 @@ TRACE_EVENT(amd_pstate_perf,
>                 __field(unsigned long, min_perf)
>                 __field(unsigned long, target_perf)
>                 __field(unsigned long, capacity)
> +               __field(unsigned long long, freq)
> +               __field(unsigned long long, mperf)
> +               __field(unsigned long long, aperf)
> +               __field(unsigned long long, tsc)
>                 __field(unsigned int, cpu_id)
>                 __field(bool, changed)
>                 __field(bool, fast_switch)
> @@ -53,15 +65,23 @@ TRACE_EVENT(amd_pstate_perf,
>                 __entry->min_perf = min_perf;
>                 __entry->target_perf = target_perf;
>                 __entry->capacity = capacity;
> +               __entry->freq = freq;
> +               __entry->mperf = mperf;
> +               __entry->aperf = aperf;
> +               __entry->tsc = tsc;
>                 __entry->cpu_id = cpu_id;
>                 __entry->changed = changed;
>                 __entry->fast_switch = fast_switch;
>                 ),
>
> -       TP_printk("amd_min_perf=%lu amd_des_perf=%lu amd_max_perf=%lu cpu_id=%u changed=%s fast_switch=%s",
> +       TP_printk("amd_min_perf=%lu amd_des_perf=%lu amd_max_perf=%lu freq=%llu mperf=%llu aperf=%llu tsc=%llu cpu_id=%u changed=%s fast_switch=%s",
>                   (unsigned long)__entry->min_perf,
>                   (unsigned long)__entry->target_perf,
>                   (unsigned long)__entry->capacity,
> +                 (unsigned long long)__entry->freq,
> +                 (unsigned long long)__entry->mperf,
> +                 (unsigned long long)__entry->aperf,
> +                 (unsigned long long)__entry->tsc,
>                   (unsigned int)__entry->cpu_id,
>                   (__entry->changed) ? "true" : "false",
>                   (__entry->fast_switch) ? "true" : "false"
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 9ce75ed11f8e..7be38bc6a673 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -65,6 +65,18 @@ MODULE_PARM_DESC(shared_mem,
>
>  static struct cpufreq_driver amd_pstate_driver;
>
> +/**
> + * struct  amd_aperf_mperf
> + * @aperf: actual performance frequency clock count
> + * @mperf: maximum performance frequency clock count
> + * @tsc:   time stamp counter
> + */
> +struct amd_aperf_mperf {
> +       u64 aperf;
> +       u64 mperf;
> +       u64 tsc;
> +};
> +
>  /**
>   * struct amd_cpudata - private CPU data for AMD P-State
>   * @cpu: CPU number
> @@ -81,6 +93,9 @@ static struct cpufreq_driver amd_pstate_driver;
>   * @min_freq: the frequency that mapped to lowest_perf
>   * @nominal_freq: the frequency that mapped to nominal_perf
>   * @lowest_nonlinear_freq: the frequency that mapped to lowest_nonlinear_perf
> + * @cur: Difference of Aperf/Mperf/tsc count between last and current sample
> + * @prev: Last Aperf/Mperf/tsc count value read from register
> + * @freq: current cpu frequency value
>   * @boost_supported: check whether the Processor or SBIOS supports boost mode
>   *
>   * The amd_cpudata is key private data for each CPU thread in AMD P-State, and
> @@ -102,6 +117,10 @@ struct amd_cpudata {
>         u32     nominal_freq;
>         u32     lowest_nonlinear_freq;
>
> +       struct amd_aperf_mperf cur;
> +       struct amd_aperf_mperf prev;
> +
> +       u64 freq;
>         bool    boost_supported;
>  };
>
> @@ -211,6 +230,39 @@ static inline void amd_pstate_update_perf(struct amd_cpudata *cpudata,
>                                             max_perf, fast_switch);
>  }
>
> +static inline bool amd_pstate_sample(struct amd_cpudata *cpudata)
> +{
> +       u64 aperf, mperf, tsc;
> +       unsigned long flags;
> +
> +       local_irq_save(flags);
> +       rdmsrl(MSR_IA32_APERF, aperf);
> +       rdmsrl(MSR_IA32_MPERF, mperf);
> +       tsc = rdtsc();
> +
> +       if (cpudata->prev.mperf == mperf || cpudata->prev.tsc == tsc) {
> +               local_irq_restore(flags);
> +               return false;
> +       }
> +
> +       local_irq_restore(flags);
> +
> +       cpudata->cur.aperf = aperf;
> +       cpudata->cur.mperf = mperf;
> +       cpudata->cur.tsc =  tsc;
> +       cpudata->cur.aperf -= cpudata->prev.aperf;
> +       cpudata->cur.mperf -= cpudata->prev.mperf;
> +       cpudata->cur.tsc -= cpudata->prev.tsc;
> +
> +       cpudata->prev.aperf = aperf;
> +       cpudata->prev.mperf = mperf;
> +       cpudata->prev.tsc = tsc;
> +
> +       cpudata->freq = div64_u64((cpudata->cur.aperf * cpu_khz), cpudata->cur.mperf);
> +
> +       return true;
> +}
> +
>  static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
>                               u32 des_perf, u32 max_perf, bool fast_switch)
>  {
> @@ -226,8 +278,11 @@ static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
>         value &= ~AMD_CPPC_MAX_PERF(~0L);
>         value |= AMD_CPPC_MAX_PERF(max_perf);
>
> -       trace_amd_pstate_perf(min_perf, des_perf, max_perf,
> -                             cpudata->cpu, (value != prev), fast_switch);
> +       if (trace_amd_pstate_perf_enabled() && amd_pstate_sample(cpudata)) {
> +               trace_amd_pstate_perf(min_perf, des_perf, max_perf, cpudata->freq,
> +                       cpudata->cur.mperf, cpudata->cur.aperf, cpudata->cur.tsc,
> +                               cpudata->cpu, (value != prev), fast_switch);
> +       }
>
>         if (value == prev)
>                 return;
> --
> 2.27.0
>
Deucher, Alexander March 1, 2022, 4:05 p.m. UTC | #2
[AMD Official Use Only]

> -----Original Message-----
> From: Rafael J. Wysocki <rafael@kernel.org>
> Sent: Tuesday, March 1, 2022 10:26 AM
> To: Su, Jinzhou (Joe) <Jinzhou.Su@amd.com>
> Cc: Rafael J. Wysocki <rjw@rjwysocki.net>; Linux PM <linux-
> pm@vger.kernel.org>; Srinivas Pandruvada
> <srinivas.pandruvada@linux.intel.com>; Doug Smythies
> <dsmythies@telus.net>; Huang, Ray <Ray.Huang@amd.com>; Viresh Kumar
> <viresh.kumar@linaro.org>; Todd Brandt <todd.e.brandt@linux.intel.com>;
> Linux Kernel Mailing List <linux-kernel@vger.kernel.org>; Sharma, Deepak
> <Deepak.Sharma@amd.com>; Deucher, Alexander
> <Alexander.Deucher@amd.com>; Du, Xiaojian <Xiaojian.Du@amd.com>;
> Yuan, Perry <Perry.Yuan@amd.com>; Meng, Li (Jassmine)
> <Li.Meng@amd.com>
> Subject: Re: [PATCH 1/3] cpufreq: amd-pstate: Add more tracepoint for AMD
> P-State module
> 
> On Wed, Feb 23, 2022 at 11:04 AM Jinzhou Su <Jinzhou.Su@amd.com>
> wrote:
> >
> > Add frequency, mperf, aperf and tsc in the trace. This can be used to
> > debug and tune the performance of AMD P-state driver.
> >
> > Use the time difference between amd_pstate_update to calculate CPU
> > frequency. There could be sleep in arch_freq_get_on_cpu, so do not use
> > it here.
> >
> > Signed-off-by: Jinzhou Su <Jinzhou.Su@amd.com>
> > Signed-off-by: Huang Rui <ray.huang@amd.com>
> 
> I'm not sure what the second sign-off is for.
> 
> If this is a maintainer's sign-off, it should be added by the maintainer himself
> and you should not add it when submitting the patch.

Both developers co-worked on the patch.  Isn't that pretty standard when you rework someone else's patch?

Alex

> 
> > ---
> >  drivers/cpufreq/amd-pstate-trace.h | 22 ++++++++++-
> >  drivers/cpufreq/amd-pstate.c       | 59
> +++++++++++++++++++++++++++++-
> >  2 files changed, 78 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/cpufreq/amd-pstate-trace.h
> > b/drivers/cpufreq/amd-pstate-trace.h
> > index 647505957d4f..35f38ae67fb1 100644
> > --- a/drivers/cpufreq/amd-pstate-trace.h
> > +++ b/drivers/cpufreq/amd-pstate-trace.h
> > @@ -27,6 +27,10 @@ TRACE_EVENT(amd_pstate_perf,
> >         TP_PROTO(unsigned long min_perf,
> >                  unsigned long target_perf,
> >                  unsigned long capacity,
> > +                u64 freq,
> > +                u64 mperf,
> > +                u64 aperf,
> > +                u64 tsc,
> >                  unsigned int cpu_id,
> >                  bool changed,
> >                  bool fast_switch
> > @@ -35,6 +39,10 @@ TRACE_EVENT(amd_pstate_perf,
> >         TP_ARGS(min_perf,
> >                 target_perf,
> >                 capacity,
> > +               freq,
> > +               mperf,
> > +               aperf,
> > +               tsc,
> >                 cpu_id,
> >                 changed,
> >                 fast_switch
> > @@ -44,6 +52,10 @@ TRACE_EVENT(amd_pstate_perf,
> >                 __field(unsigned long, min_perf)
> >                 __field(unsigned long, target_perf)
> >                 __field(unsigned long, capacity)
> > +               __field(unsigned long long, freq)
> > +               __field(unsigned long long, mperf)
> > +               __field(unsigned long long, aperf)
> > +               __field(unsigned long long, tsc)
> >                 __field(unsigned int, cpu_id)
> >                 __field(bool, changed)
> >                 __field(bool, fast_switch) @@ -53,15 +65,23 @@
> > TRACE_EVENT(amd_pstate_perf,
> >                 __entry->min_perf = min_perf;
> >                 __entry->target_perf = target_perf;
> >                 __entry->capacity = capacity;
> > +               __entry->freq = freq;
> > +               __entry->mperf = mperf;
> > +               __entry->aperf = aperf;
> > +               __entry->tsc = tsc;
> >                 __entry->cpu_id = cpu_id;
> >                 __entry->changed = changed;
> >                 __entry->fast_switch = fast_switch;
> >                 ),
> >
> > -       TP_printk("amd_min_perf=%lu amd_des_perf=%lu
> amd_max_perf=%lu cpu_id=%u changed=%s fast_switch=%s",
> > +       TP_printk("amd_min_perf=%lu amd_des_perf=%lu
> amd_max_perf=%lu
> > + freq=%llu mperf=%llu aperf=%llu tsc=%llu cpu_id=%u changed=%s
> > + fast_switch=%s",
> >                   (unsigned long)__entry->min_perf,
> >                   (unsigned long)__entry->target_perf,
> >                   (unsigned long)__entry->capacity,
> > +                 (unsigned long long)__entry->freq,
> > +                 (unsigned long long)__entry->mperf,
> > +                 (unsigned long long)__entry->aperf,
> > +                 (unsigned long long)__entry->tsc,
> >                   (unsigned int)__entry->cpu_id,
> >                   (__entry->changed) ? "true" : "false",
> >                   (__entry->fast_switch) ? "true" : "false"
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 9ce75ed11f8e..7be38bc6a673
> 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -65,6 +65,18 @@ MODULE_PARM_DESC(shared_mem,
> >
> >  static struct cpufreq_driver amd_pstate_driver;
> >
> > +/**
> > + * struct  amd_aperf_mperf
> > + * @aperf: actual performance frequency clock count
> > + * @mperf: maximum performance frequency clock count
> > + * @tsc:   time stamp counter
> > + */
> > +struct amd_aperf_mperf {
> > +       u64 aperf;
> > +       u64 mperf;
> > +       u64 tsc;
> > +};
> > +
> >  /**
> >   * struct amd_cpudata - private CPU data for AMD P-State
> >   * @cpu: CPU number
> > @@ -81,6 +93,9 @@ static struct cpufreq_driver amd_pstate_driver;
> >   * @min_freq: the frequency that mapped to lowest_perf
> >   * @nominal_freq: the frequency that mapped to nominal_perf
> >   * @lowest_nonlinear_freq: the frequency that mapped to
> > lowest_nonlinear_perf
> > + * @cur: Difference of Aperf/Mperf/tsc count between last and current
> > + sample
> > + * @prev: Last Aperf/Mperf/tsc count value read from register
> > + * @freq: current cpu frequency value
> >   * @boost_supported: check whether the Processor or SBIOS supports
> boost mode
> >   *
> >   * The amd_cpudata is key private data for each CPU thread in AMD
> > P-State, and @@ -102,6 +117,10 @@ struct amd_cpudata {
> >         u32     nominal_freq;
> >         u32     lowest_nonlinear_freq;
> >
> > +       struct amd_aperf_mperf cur;
> > +       struct amd_aperf_mperf prev;
> > +
> > +       u64 freq;
> >         bool    boost_supported;
> >  };
> >
> > @@ -211,6 +230,39 @@ static inline void amd_pstate_update_perf(struct
> amd_cpudata *cpudata,
> >                                             max_perf, fast_switch);  }
> >
> > +static inline bool amd_pstate_sample(struct amd_cpudata *cpudata) {
> > +       u64 aperf, mperf, tsc;
> > +       unsigned long flags;
> > +
> > +       local_irq_save(flags);
> > +       rdmsrl(MSR_IA32_APERF, aperf);
> > +       rdmsrl(MSR_IA32_MPERF, mperf);
> > +       tsc = rdtsc();
> > +
> > +       if (cpudata->prev.mperf == mperf || cpudata->prev.tsc == tsc) {
> > +               local_irq_restore(flags);
> > +               return false;
> > +       }
> > +
> > +       local_irq_restore(flags);
> > +
> > +       cpudata->cur.aperf = aperf;
> > +       cpudata->cur.mperf = mperf;
> > +       cpudata->cur.tsc =  tsc;
> > +       cpudata->cur.aperf -= cpudata->prev.aperf;
> > +       cpudata->cur.mperf -= cpudata->prev.mperf;
> > +       cpudata->cur.tsc -= cpudata->prev.tsc;
> > +
> > +       cpudata->prev.aperf = aperf;
> > +       cpudata->prev.mperf = mperf;
> > +       cpudata->prev.tsc = tsc;
> > +
> > +       cpudata->freq = div64_u64((cpudata->cur.aperf * cpu_khz),
> > + cpudata->cur.mperf);
> > +
> > +       return true;
> > +}
> > +
> >  static void amd_pstate_update(struct amd_cpudata *cpudata, u32
> min_perf,
> >                               u32 des_perf, u32 max_perf, bool
> > fast_switch)  { @@ -226,8 +278,11 @@ static void
> > amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
> >         value &= ~AMD_CPPC_MAX_PERF(~0L);
> >         value |= AMD_CPPC_MAX_PERF(max_perf);
> >
> > -       trace_amd_pstate_perf(min_perf, des_perf, max_perf,
> > -                             cpudata->cpu, (value != prev), fast_switch);
> > +       if (trace_amd_pstate_perf_enabled() &&
> amd_pstate_sample(cpudata)) {
> > +               trace_amd_pstate_perf(min_perf, des_perf, max_perf, cpudata-
> >freq,
> > +                       cpudata->cur.mperf, cpudata->cur.aperf, cpudata->cur.tsc,
> > +                               cpudata->cpu, (value != prev), fast_switch);
> > +       }
> >
> >         if (value == prev)
> >                 return;
> > --
> > 2.27.0
> >
Rafael J. Wysocki March 1, 2022, 4:07 p.m. UTC | #3
On Tue, Mar 1, 2022 at 5:05 PM Deucher, Alexander
<Alexander.Deucher@amd.com> wrote:
>
> [AMD Official Use Only]
>
> > -----Original Message-----
> > From: Rafael J. Wysocki <rafael@kernel.org>
> > Sent: Tuesday, March 1, 2022 10:26 AM
> > To: Su, Jinzhou (Joe) <Jinzhou.Su@amd.com>
> > Cc: Rafael J. Wysocki <rjw@rjwysocki.net>; Linux PM <linux-
> > pm@vger.kernel.org>; Srinivas Pandruvada
> > <srinivas.pandruvada@linux.intel.com>; Doug Smythies
> > <dsmythies@telus.net>; Huang, Ray <Ray.Huang@amd.com>; Viresh Kumar
> > <viresh.kumar@linaro.org>; Todd Brandt <todd.e.brandt@linux.intel.com>;
> > Linux Kernel Mailing List <linux-kernel@vger.kernel.org>; Sharma, Deepak
> > <Deepak.Sharma@amd.com>; Deucher, Alexander
> > <Alexander.Deucher@amd.com>; Du, Xiaojian <Xiaojian.Du@amd.com>;
> > Yuan, Perry <Perry.Yuan@amd.com>; Meng, Li (Jassmine)
> > <Li.Meng@amd.com>
> > Subject: Re: [PATCH 1/3] cpufreq: amd-pstate: Add more tracepoint for AMD
> > P-State module
> >
> > On Wed, Feb 23, 2022 at 11:04 AM Jinzhou Su <Jinzhou.Su@amd.com>
> > wrote:
> > >
> > > Add frequency, mperf, aperf and tsc in the trace. This can be used to
> > > debug and tune the performance of AMD P-state driver.
> > >
> > > Use the time difference between amd_pstate_update to calculate CPU
> > > frequency. There could be sleep in arch_freq_get_on_cpu, so do not use
> > > it here.
> > >
> > > Signed-off-by: Jinzhou Su <Jinzhou.Su@amd.com>
> > > Signed-off-by: Huang Rui <ray.huang@amd.com>
> >
> > I'm not sure what the second sign-off is for.
> >
> > If this is a maintainer's sign-off, it should be added by the maintainer himself
> > and you should not add it when submitting the patch.
>
> Both developers co-worked on the patch.  Isn't that pretty standard when you rework someone else's patch?

It is, but that's when Co-developed-by should be used.  Otherwise the
meaning of the second s-o-b is unclear.
Jinzhou Su March 2, 2022, 9:53 a.m. UTC | #4
[AMD Official Use Only]

Comment in line.

Regards,
Joe

> -----Original Message-----
> From: Huang, Ray <Ray.Huang@amd.com>
> Sent: Wednesday, March 2, 2022 5:09 PM
> To: Rafael J. Wysocki <rafael@kernel.org>; Su, Jinzhou (Joe)
> <Jinzhou.Su@amd.com>
> Cc: Deucher, Alexander <Alexander.Deucher@amd.com>; Rafael J. Wysocki
> <rjw@rjwysocki.net>; Linux PM <linux-pm@vger.kernel.org>; Srinivas
> Pandruvada <srinivas.pandruvada@linux.intel.com>; Doug Smythies
> <dsmythies@telus.net>; Viresh Kumar <viresh.kumar@linaro.org>; Todd
> Brandt <todd.e.brandt@linux.intel.com>; Linux Kernel Mailing List <linux-
> kernel@vger.kernel.org>; Sharma, Deepak <Deepak.Sharma@amd.com>; Du,
> Xiaojian <Xiaojian.Du@amd.com>; Yuan, Perry <Perry.Yuan@amd.com>;
> Meng, Li (Jassmine) <Li.Meng@amd.com>
> Subject: Re: [PATCH 1/3] cpufreq: amd-pstate: Add more tracepoint for AMD P-
> State module
>
> On Wed, Mar 02, 2022 at 12:07:45AM +0800, Rafael J. Wysocki wrote:
> > On Tue, Mar 1, 2022 at 5:05 PM Deucher, Alexander
> > <Alexander.Deucher@amd.com> wrote:
> > >
> > > [AMD Official Use Only]
> > >
> > > > -----Original Message-----
> > > > From: Rafael J. Wysocki <rafael@kernel.org>
> > > > Sent: Tuesday, March 1, 2022 10:26 AM
> > > > To: Su, Jinzhou (Joe) <Jinzhou.Su@amd.com>
> > > > Cc: Rafael J. Wysocki <rjw@rjwysocki.net>; Linux PM <linux-
> > > > pm@vger.kernel.org>; Srinivas Pandruvada
> > > > <srinivas.pandruvada@linux.intel.com>; Doug Smythies
> > > > <dsmythies@telus.net>; Huang, Ray <Ray.Huang@amd.com>; Viresh
> > > > Kumar <viresh.kumar@linaro.org>; Todd Brandt
> > > > <todd.e.brandt@linux.intel.com>; Linux Kernel Mailing List
> > > > <linux-kernel@vger.kernel.org>; Sharma, Deepak
> > > > <Deepak.Sharma@amd.com>; Deucher, Alexander
> > > > <Alexander.Deucher@amd.com>; Du, Xiaojian <Xiaojian.Du@amd.com>;
> > > > Yuan, Perry <Perry.Yuan@amd.com>; Meng, Li (Jassmine)
> > > > <Li.Meng@amd.com>
> > > > Subject: Re: [PATCH 1/3] cpufreq: amd-pstate: Add more tracepoint
> > > > for AMD P-State module
> > > >
> > > > On Wed, Feb 23, 2022 at 11:04 AM Jinzhou Su <Jinzhou.Su@amd.com>
> > > > wrote:
> > > > >
> > > > > Add frequency, mperf, aperf and tsc in the trace. This can be
> > > > > used to debug and tune the performance of AMD P-state driver.
> > > > >
> > > > > Use the time difference between amd_pstate_update to calculate
> > > > > CPU frequency. There could be sleep in arch_freq_get_on_cpu, so
> > > > > do not use it here.
> > > > >
> > > > > Signed-off-by: Jinzhou Su <Jinzhou.Su@amd.com>
> > > > > Signed-off-by: Huang Rui <ray.huang@amd.com>
> > > >
> > > > I'm not sure what the second sign-off is for.
> > > >
> > > > If this is a maintainer's sign-off, it should be added by the
> > > > maintainer himself and you should not add it when submitting the patch.
> > >
> > > Both developers co-worked on the patch.  Isn't that pretty standard when
> you rework someone else's patch?
> >
> > It is, but that's when Co-developed-by should be used.  Otherwise the
> > meaning of the second s-o-b is unclear.
>
> Yes.
>
> Joe, can you add below in next V2:
>
> Co-developed-by: Huang Rui <ray.huang@amd.com>
>
> Patch looks good for me, could you please add new patch to describe how to
> use the tracer script in Documentation/admin-guide/pm/amd-pstate.rst?

Ok, will do that later.

Joe
>
> Thanks,
> Ray
diff mbox series

Patch

diff --git a/drivers/cpufreq/amd-pstate-trace.h b/drivers/cpufreq/amd-pstate-trace.h
index 647505957d4f..35f38ae67fb1 100644
--- a/drivers/cpufreq/amd-pstate-trace.h
+++ b/drivers/cpufreq/amd-pstate-trace.h
@@ -27,6 +27,10 @@  TRACE_EVENT(amd_pstate_perf,
 	TP_PROTO(unsigned long min_perf,
 		 unsigned long target_perf,
 		 unsigned long capacity,
+		 u64 freq,
+		 u64 mperf,
+		 u64 aperf,
+		 u64 tsc,
 		 unsigned int cpu_id,
 		 bool changed,
 		 bool fast_switch
@@ -35,6 +39,10 @@  TRACE_EVENT(amd_pstate_perf,
 	TP_ARGS(min_perf,
 		target_perf,
 		capacity,
+		freq,
+		mperf,
+		aperf,
+		tsc,
 		cpu_id,
 		changed,
 		fast_switch
@@ -44,6 +52,10 @@  TRACE_EVENT(amd_pstate_perf,
 		__field(unsigned long, min_perf)
 		__field(unsigned long, target_perf)
 		__field(unsigned long, capacity)
+		__field(unsigned long long, freq)
+		__field(unsigned long long, mperf)
+		__field(unsigned long long, aperf)
+		__field(unsigned long long, tsc)
 		__field(unsigned int, cpu_id)
 		__field(bool, changed)
 		__field(bool, fast_switch)
@@ -53,15 +65,23 @@  TRACE_EVENT(amd_pstate_perf,
 		__entry->min_perf = min_perf;
 		__entry->target_perf = target_perf;
 		__entry->capacity = capacity;
+		__entry->freq = freq;
+		__entry->mperf = mperf;
+		__entry->aperf = aperf;
+		__entry->tsc = tsc;
 		__entry->cpu_id = cpu_id;
 		__entry->changed = changed;
 		__entry->fast_switch = fast_switch;
 		),
 
-	TP_printk("amd_min_perf=%lu amd_des_perf=%lu amd_max_perf=%lu cpu_id=%u changed=%s fast_switch=%s",
+	TP_printk("amd_min_perf=%lu amd_des_perf=%lu amd_max_perf=%lu freq=%llu mperf=%llu aperf=%llu tsc=%llu cpu_id=%u changed=%s fast_switch=%s",
 		  (unsigned long)__entry->min_perf,
 		  (unsigned long)__entry->target_perf,
 		  (unsigned long)__entry->capacity,
+		  (unsigned long long)__entry->freq,
+		  (unsigned long long)__entry->mperf,
+		  (unsigned long long)__entry->aperf,
+		  (unsigned long long)__entry->tsc,
 		  (unsigned int)__entry->cpu_id,
 		  (__entry->changed) ? "true" : "false",
 		  (__entry->fast_switch) ? "true" : "false"
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 9ce75ed11f8e..7be38bc6a673 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -65,6 +65,18 @@  MODULE_PARM_DESC(shared_mem,
 
 static struct cpufreq_driver amd_pstate_driver;
 
+/**
+ * struct  amd_aperf_mperf
+ * @aperf: actual performance frequency clock count
+ * @mperf: maximum performance frequency clock count
+ * @tsc:   time stamp counter
+ */
+struct amd_aperf_mperf {
+	u64 aperf;
+	u64 mperf;
+	u64 tsc;
+};
+
 /**
  * struct amd_cpudata - private CPU data for AMD P-State
  * @cpu: CPU number
@@ -81,6 +93,9 @@  static struct cpufreq_driver amd_pstate_driver;
  * @min_freq: the frequency that mapped to lowest_perf
  * @nominal_freq: the frequency that mapped to nominal_perf
  * @lowest_nonlinear_freq: the frequency that mapped to lowest_nonlinear_perf
+ * @cur: Difference of Aperf/Mperf/tsc count between last and current sample
+ * @prev: Last Aperf/Mperf/tsc count value read from register
+ * @freq: current cpu frequency value
  * @boost_supported: check whether the Processor or SBIOS supports boost mode
  *
  * The amd_cpudata is key private data for each CPU thread in AMD P-State, and
@@ -102,6 +117,10 @@  struct amd_cpudata {
 	u32	nominal_freq;
 	u32	lowest_nonlinear_freq;
 
+	struct amd_aperf_mperf cur;
+	struct amd_aperf_mperf prev;
+
+	u64 freq;
 	bool	boost_supported;
 };
 
@@ -211,6 +230,39 @@  static inline void amd_pstate_update_perf(struct amd_cpudata *cpudata,
 					    max_perf, fast_switch);
 }
 
+static inline bool amd_pstate_sample(struct amd_cpudata *cpudata)
+{
+	u64 aperf, mperf, tsc;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	rdmsrl(MSR_IA32_APERF, aperf);
+	rdmsrl(MSR_IA32_MPERF, mperf);
+	tsc = rdtsc();
+
+	if (cpudata->prev.mperf == mperf || cpudata->prev.tsc == tsc) {
+		local_irq_restore(flags);
+		return false;
+	}
+
+	local_irq_restore(flags);
+
+	cpudata->cur.aperf = aperf;
+	cpudata->cur.mperf = mperf;
+	cpudata->cur.tsc =  tsc;
+	cpudata->cur.aperf -= cpudata->prev.aperf;
+	cpudata->cur.mperf -= cpudata->prev.mperf;
+	cpudata->cur.tsc -= cpudata->prev.tsc;
+
+	cpudata->prev.aperf = aperf;
+	cpudata->prev.mperf = mperf;
+	cpudata->prev.tsc = tsc;
+
+	cpudata->freq = div64_u64((cpudata->cur.aperf * cpu_khz), cpudata->cur.mperf);
+
+	return true;
+}
+
 static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
 			      u32 des_perf, u32 max_perf, bool fast_switch)
 {
@@ -226,8 +278,11 @@  static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
 	value &= ~AMD_CPPC_MAX_PERF(~0L);
 	value |= AMD_CPPC_MAX_PERF(max_perf);
 
-	trace_amd_pstate_perf(min_perf, des_perf, max_perf,
-			      cpudata->cpu, (value != prev), fast_switch);
+	if (trace_amd_pstate_perf_enabled() && amd_pstate_sample(cpudata)) {
+		trace_amd_pstate_perf(min_perf, des_perf, max_perf, cpudata->freq,
+			cpudata->cur.mperf, cpudata->cur.aperf, cpudata->cur.tsc,
+				cpudata->cpu, (value != prev), fast_switch);
+	}
 
 	if (value == prev)
 		return;